The present invention relates to a tread for heavy-duty radial carcass tires, in particular for heavy vehicles intended to travel both on the highway and on different terrains.
Experience shows that the treads of radial tires for heavy vehicles intended for mixed road/construction-site travel are subject, due to the severe constraints to which they are subjected, on the one hand to extensive wear of the side zones which takes the form of a breakdown of the edges of the tread and, on the other hand, an abnormal saw-tooth wear. These two types of wear are particularly substantial on the treads of tires mounted on the drive axles of the vehicle, whether in individual or in twin mounting.
These two types of wears are greater when the tread essentially comprises individual blocks which produce better adherence to movable soil to the detriment of accelerated wear on the highway.
In order to reduce abnormal wear of a tread formed of individual blocks separated by grooves from each other, it has been proposed in British Patent Application 2 008 043 to arrange bridges of rubber in the side transverse grooves provided with a fine incision, and this on both sides of a narrow circumferential groove of the same depth as the two wide circumferential grooves separating two adjacent blocks in the transverse direction.
Such a solution, to be sure, results in a gain in wear due to the bridge effect which takes place between the blocks in the area of contact with the ground but to the detriment of the adherence on diversified terrain, and this without preventing a rather rapid breakdown of the edges of the tread.